Figure 2. Rainfall in HPE#1 (2-5 Nov 1991). (a) Total rainfall for the historic simulation (see Armon et al. (2020): Fig. 7 for a comparison with precipitation measured by the weather radar). (b) Total rainfall for the future (PGW) simulation. (c) Difference between historic and future simulations (future – historic). (d) Upper 1% quantile of the cumulative frequency curve of unconditional 10-min rain rates throughout the event (i.e., including no-rain intervals and pixels) for the historic (blue line) and future (orange) events. The dashed yellow line marks their intersection. The small inset presents the full cumulative frequency curve of conditional 10-min rain rates (where rain rate >0.1 mm h-1), with mean rain rates in dashed lines. (e) Time series of the areal coverage of rainfall (% of the area covered by rain rate >0.1 mm h-1). Note the larger historic relative to the future unconditional rain rates (up to the 99.75% quantile [marked with yellow dashed line]; panel d) and the rain area (e) while future conditional rain rates are larger throughout the distribution (inset in d and Fig. S2a).
3.2 Decreased Rainfall Accumulation Throughout Events
In general, future simulations show a significant decrease in rainfall accumulation compared with historic simulations (Fig. 3), with a sum of the areal average over all 41 events of 485 mm, compared to 601 mm, respectively (-19%). This decrease is seen throughout the region, with >90% of the area exhibiting decreased rainfall. Given the large variability in rainfall in the region (inter-annual, inter- and intra-event), the fact that 35% of the area shows a significant change in rainfall accumulation highlights the robustness of the results. Out of the portion of pixels showing a statistically significant change, 99.97% exhibit a decrease in total rainfall. In absolute terms, this decrease is most severe in the wetter part of the region (the northern area and the mountains); 1% of pixels show a decrease of ≥618 mm (Fig. 3c). In relative terms, the decrease is most drastic over the Sinai desert and throughout Jordan; 1% of pixels show a decrease of at least 55% (Fig. 3d).